Glass washing composition



Patented May 13, 1941' GLASS WASHING COMPOSITION William C. Cooper, Waukesha, Wis., assignor to George J. Meyer Manufacturing Company, Cudahy, Wis., a corporation ofWisconsin N Drawing. Application January 5, 1949, Serial No. 312,573

(Cl. 252---156)v 6 Claims.

This invention relates to washing compositions and solutions, and more particularly to a composition adapted for use in glass washing machines.

In machines to wash glass bottles, it has been common practice to use a caustic which will soak the dirt out of the bottles and leave them antiseptically clean. For this purpose a 3% to 6% solution of caustic soda (NaOH) has proved the most efiective due to its relatively low cost. To this caustic solution one or more of the so-calld mild alkalies has usually been added to facilitate rinsing.

It has been found that ordinary glass bottles are somewhat soluble in these solutions, and that as the bottles move in their carriers the solution softens the surfaces of the bottles permitting the metal parts of the machine to scratch the softened bottle surfaces, weakening the bottles and rendering them unsightly. Such bottles soon have to be discarded or burst while in use.

A further disadvantage of the solutions is,

found during rinsing of the bottles. The water used in rinsing usually contains a small amount of magnesium salts, and when the bottles are rinsed such salts combine with the vcaustic solution to form magnesium hydroxide [Mg(OH) 2]. The magnesium hydroxide precipitates on the bottles in the form of a sticky white substance which is difiicult to remove and which leaves the bottles cloudy and gray.

In order to try to prevent the formation of the magnesium hydroxide during rinsing, various mild alkalies such as phosphates have been added to the caustic or used in the final washing compartment. Such alkalies have proved unsatisfactory due to the fact that theglass is highly soluble therein and consequently is much more easily scratched and marred.

One object of the present invention is to devise a washing composition and solution which will reduce scratching of the bottles during wash- Another object is to devise a washing composition and solution which will leave the bottles clear and clean after rinsing with hard water.

A further object is to devise a washing composition and solution which will give more eiiective wetting of the bottles.

A further object is to devise a washing composition and solution which will reduce marring of the bottles.

A further object is to devise a washing composition and solution which will reduce the amount of glass dissolved.

- A further object is to devise a washing composition and solution which will be relatively economical to manufacture.

A further object is to devise a washing compositionand solution which may be varied by the user to suit his particular conditions.

Other objects will become apparent from the following description.

It has been found, after extensive experiments, that scratching of glass bottles in mechanical bottle washing machines is due primarily to solubility ofthe glass in the washing solutions. To remedy this condition it has been found that if a small percentage of a. soluble alkaline aluminate, such as sodium aluminate, (NaaAlOa, NaAlOz or NazAlzOr), potassium aluminate (KaAlOs, KAlOz or K2A12O4), or lithium aluminate (LlsAlOs, LiAlOz or Ll2A12O4) be added to the caustic solution that this aluminate reduces the solubility of the glass in the'caustic solution and acts as a wetting agent to reduce the surface tension on the bottles and thus promote thorough washing thereof.

It has been found further that the addition of the soluble alkaline aluminate aids in rinsing the bottles bycombining with the magnesium to form magnesium aluminate Mg(AlO2)2] which is a light fiocculent agent, and does not adhere to the glass and hence is readily flushed away to leave the bottles clear and clean.

In practice it has been found most economical to use sodium aluminate in the present washing solution due to its relatively small cost, but the other aluminates are equally efiective in the composition.

The present washing solution comprises:

Ihe above percentages represent the amount of salts and water in the washing solution. The washing composition may be prepared by mixing the salts together previously to dissolving them in water or they may be added individually and separately to the water in the proportions indicated according to the composition of the wa ter.

When the washing composition is to be prepared previously to dissolving in water the following proportions of salts should be used:

Per cent Caustic '70 to Soluble alkaline aluminate 5 to 30 The mixed salt is then dissolved in water so that the water contains 3% to 7% by weight of the mixture.

It will be understood that the above proportions are more or less flexible. The proportions of caustic soda (NaOH) given represent the prac tical range which will give a clean, germ free bottle without serious scratching or abrasion marks.- The proportion of aluminate represents the amount which is effective in preventing scratching and abrasion of the bottle. Less than one quarter of one percent aluminate in solution does not act effectively to prevent abrasion and scratching in the caustic solution, while amounts in excess of one percent fail to give comparable increases in protection to the glass surface.

The proportion of caustic and aluminate which has been found to give the most satisfactory results in general is:

Per cent Caustic soda 2 /2 Soluble alkaline aluminate /2 Water 97 l. A glass washing solution comprising the following ingredients in substantially the indicated proportions by weight:

Per cent Caustic soda 2 /2 to 6 Water-soluble alkaline aluminate"... to 1 Water 93 to 97 2. A glass washing solution comprising the 01- lowing ingredients in substantially the indicated proportions by weight:

Per cent Caustic soda 2 A to 6 Sodium aluminate to 1 Water 93 to 97 3. A glass washing solution comprising the folg lowing ingredients in substantially the indicated proportions by weight:

Per cent Caustic soda 2 to 6 Potassium aluminate A; to 1 Water 93 to 97 4. A glass washing solution comprising the following ingredients in substantially the indicated proportions by weight:

Per cent Caustic soda 2 to 6 Lithium aluminate to 1 Water 93 to 9'7 5. A glass washing solution comprising the following ingredients in substantially the indicated proportions by weight:

Per cent Caustic' soda 2 Water-soluble alkaline aluminate Water 97 6. A glass washing solution comprising the following ingredients in substantially the indicated proportions by weight:

Per cent Caustic soda 2 /2 Sodium aluminate Water 97 WILLIAM C. COOPER. 

